As disclosed in German Pat. No. 1,129,281 (Nischk et al.), it is known that epoxy resins can be cured with aromatic diamines and that certain advantages can be achieved by the use of 1-alkylthio-2,4-diaminobenzenes as the diamine curing agents. However, it has been found that the 1-alkylthio-2,4-diaminobenzenes of Nischk et al. are more reactive than is sometimes desired, e.g., when the curing agent is to be used in preparing prepregs.
U.S. Pat. No. 4,595,742 (Nalepa et al.) teaches that polyurethanes can be cured with aromatic diamines bearing more than one ar-alkylthio substituent.